Neurologic disorders including cervical spinal cord injury, brainstem stroke, and amyotrophic lateral sclerosis can lead to severe paralysis of all fou limbs. More than 100,000 people in the US have tetraplegia from these and other disorders, which in their most extreme forms can lead to loss of all voluntary movement and the loss of speech (locked-in syndrome). Over the past 10 years, intracortically based brain-computer interfaces have been developed with the hope of restoring voluntary, intuitive, flexible, and around-the-clock control of external devices such as a computer cursor, or internal neuromuscular stimulators capable of reanimating limb movement. In humans, conveying these powerful, high-bandwidth, intracranially recorded neural signals to external neural decoders has required percutaneous components that tether the user to nearby technologies and require regular caregiver assistance to reduce the risk of infection. We have created and performed initial nonclinical testing of a fully implanted, high bandwidth neural recording system that can transmit 100 channels of neuronal ensemble data to receivers up to 1 meter away. This tightly collaborative, multi-institutional project brings together leaders in neurology, neurosurgery, neuroscience, neuroengineering, and medical device clinical trials to (1) complete the manufacture and regulatory assessment of this next- generation technology, and (2) perform a rigorous Early Feasibility Study in which six participants with tetraplegia will test the investigational BrainGate3 Neural Interface System, at home, for at least one year. This study will provide early clinical experience with a novel neurotechnology platform, and will inform the development of next-generation closed-loop neural recording and stimulating devices to help manage the symptoms of neurologic and neuropsychiatric disease.